[BUG] srt-live-transmit stops listening after SRT disconnect during no active input

[Frenzie]

Describe the bug
srt-live-transmit stops listening on the configured port if the SRT connection was closed at a moment when there was no input

To Reproduce
Steps to reproduce the behavior:

1. Start srt-live-transmit and stop sending input. Or to simulate, just pipe nothing into it: cat | srt-live-transmit -v "file://con srt://127.0.0.1:5000?mode=listener
2. Start a receiver: srt-live-transmit -v srt://127.0.0.1:5000?mode=caller udp://127.0.0.1:5001
3. Stop the receiver

If you now try to reconnect or check with for example netstat -anu | grep 5000 you'll see the bind has disappeared.

Expected behavior
The listener never stops listening on the configured port.

Desktop (please provide the following information):

• OS: Linux (Debian 12, Ubuntu 24.04)
• SRT Version / commit ID: 1.5.3